The U.S. Civil War and emancipation wiped out a substantial fraction of southern wealth. The prevailing view of most economic historians, however, is that the southern planter elite was able to retain its relative status despite these shocks. Previous studies have been hampered, however, by limits on the ability to link individuals between census years, and have been forced to focus on persistence within one or a few counties. Recent advances in electronic access to the Federal Census manuscripts now make it possible to link individuals without these constraints. We exploit the ability to search the full manuscript census to construct a sample that links top wealth holders in 1870 to their 1860 census records. Although there was an entrenched southern planter elite that retained their economic status, we find evidence that the turmoil of 1860s opened greater opportunities for mobility in the South than was the case in the North, resulting in much greater turnover among wealthy southerners than among comparably wealthy northerners. [. . .]

Comparing the two regions, it is apparent that there was considerably more turnover among the ranks of top southern wealth holders than among northern wealth holders. While more than half of the those in the top 5 percent of northern wealth holders had been in the same group in 1860 just one-third of top southern wealth holders in 1870 had enjoyed a similar status in 1860. Roughly the same proportion of the top 5 percent in each region was drawn from the next stratum of wealth holders in 1860 (90th to 95th percentile). On the other hand, our data suggest that the turmoil of the Civil War decade created much greater opportunities for those with moderate wealth in 1860 – between the 55th and 90th percentiles – to move up to the top of the wealth distribution. Nearly 40 percent of the wealthiest southerners in 1870 had been in this group in 1860, compared to less than one quarter of the richest northerners.

The Impact of the Civil War on Southern Wealth Holders. Brandon Dupont, Joshua Rosenbloom. NBER Working Paper No. 22184. Issued in April 2016. http://www.nber.org/papers/w22184

We next analyzed UK Biobank population structure in conjunction with ancient DNA samples.
Modern European populations are known to have descended from three ancestral populations:
Steppe, Mesolithic Europeans and Neolithic farmers 21,22 . We projected ancient samples from
these three populations as well as ancient Saxon samples 24 onto the UK Biobank PCs (Figure 3,
Supplementary Figure 4, see Online Methods). These populations were primarily differentiated
along PC1 and PC3, indicating higher levels of Steppe ancestry in northern UK populations.

Additionally, the lack of any ancient sample correlation with PC2 suggests that Welsh
populations are not differentially admixed with any ancient population in our data set, and
likely underwent Welsh-specific genetic drift. We confirmed these findings by projecting pan-
European POPRES 26 samples onto the UK Biobank PCs (see Online Methods, Supplementary
Figure 5) noting that of the continental European populations, Russians (who have the most
Steppe ancestry) lie on one side and Spanish and Italians (who have least) 22 lie on the other side
along PC1 and PC3, and that none of the continental European populations projected onto the
same regions as the Welsh on PC2 and PC5.

In addition to the impact of ancient Eurasian populations, we know that the genetics of the UK
has been strongly impacted by Anglo-Saxon migrations since the Iron Age 24 , with the Angles
arriving in eastern England and the Saxons in southern England. The Anglo-Saxons interbred
with the native Celts, which explains much of the genetic landscape in the UK. We analyzed a
variety of samples from Celtic (Scotland and Wales) and Anglo-Saxon (southern and eastern
England) populations from modern Britain in conjunction with the PoBI samples 20 and 10
ancient Saxon samples from eastern England 24 in order to assess the relative amounts of Steppe
ancestry. [. . .] We consistently obtained significantly
positive f4 statistics, implying that both the modern Celtic samples and the ancient Saxon
samples have more Steppe ancestry than the modern Anglo-Saxon samples from southern and
eastern England. This indicates that southern and eastern England is not exclusively a genetic
mix of Celts and Saxons. There are a variety of possible explanations, but one is that the present
genetic structure of Britain, while subtle, is quite old, and that southern England in Roman
times already had less Steppe ancestry than Wales and Scotland.

Note: I find it unlikely the pattern they observe is a holdover from Roman times. I suspect it will turn out the decrement of Steppe ancestry in England stems from a continual trickle of continental genes into England over the past 1000 years (from which the fringes of the British Isles were comparatively isolated).

Also supports my impression that the Wellcome Trust paper still overestimated the degree of Iron Age British admixture in modern England (given that the authors had assumed a simple two-way admixture, while the authors of the above preprint provide evidence "southern and eastern England is not exclusively a genetic mix of Celts and Saxons").

Family and twin studies suggest that up to 50% of individual differences in human fertility within a population might be heritable. However, it remains unclear whether the genes associated with fertility outcomes such as number of children ever born (NEB) or age at first birth (AFB) are the same across geographical and historical environments. By not taking this into account, previous genetic studies implicitly assumed that the genetic effects are constant across time and space. We conduct a mega-analysis applying whole genome methods on 31,396 unrelated men and women from six Western countries. Across all individuals and environments, common single-nucleotide polymorphisms (SNPs) explained only ~4% of the variance in NEB and AFB. We then extend these models to test whether genetic effects are shared across different environments or unique to them. For individuals belonging to the same population and demographic cohort (born before or after the 20th century fertility decline), SNP-based heritability was almost five times higher at 22% for NEB and 19% for AFB. We also found no evidence suggesting that genetic effects on fertility are shared across time and space. Our findings imply that the environment strongly modifies genetic effects on the tempo and quantum of fertility, that currently ongoing natural selection is heterogeneous across environments, and that gene-environment interactions may partly account for missing heritability in fertility. Future research needs to combine efforts from genetic research and from the social sciences to better understand human fertility.

Facial width-to-height ratio (fWHR) is not associated with pubertal testosterone

Several researchers have proposed that facial width-to-height ratio (fWHR) is a sexually dimorphic signal that develops under the influence of pubertal testosterone (T); however, this hypothesis is currently under supported. Here we examine the association between fWHR and T during the period of the life span when facial growth is canalized--adolescence. To do so, we examine the association between T, known T-derived traits (i.e. strength and voice pitch), and craniofacial measurements in a sample of adolescent Tsimane males. If fWHR variation derives from pubertal T’s influence on craniofacial growth, several predictions can be made: 1) fWHR should increase with age as T increases, 2) fWHR should reflect adolescent T (rather than adult T per se), 3) fWHR should exhibit a growth spurt in parallel with T, 4) fWHR and T should correlate after controlling for potential confounds, and 5) fWHR should show a strong relationship to other T-derived traits. These effects were not observed. We also examined three additional facial masculinity ratios: facial width/lower face height, cheekbone prominence, and facial width/full face height. In contrast to fWHR, each of the three additional measures exhibit a strong age-related pattern of change and are associated with both T and T-dependent traits. In summary, our results challenge the status of fWHR as a sexually-selected signal of pubertal T and T-linked traits.

The relationship between social status, body size, and salivary hormone levels among Garisakang forager-horticulturalist men of lowland Papua New Guinea

Social hierarchy is a robust phenomenon that exists within all human societies. Over the past several decades, a growing body of evidence from industrialized Western populations has suggested that social status is closely related to individual measures of stress, health, and many other fitness-related traits. Data regarding such relationships, however, remain rare among small-scale subsistence societies, preventing a clear understanding of the importance of social position for fitness cross-culturally. Here we contribute to this area of research by exploring the relationship between adult male social status, BMI, and levels of salivary testosterone and diurnal cortisol among Garisakang small-scale forager-horticulturalists of lowland Papua New Guinea (N = 32). Three measures of individual social status – Respect, Dominance and Prosociality – were extracted from principal components analysis of photo-rank data for locally valued male traits (e.g., sociability, hunting ability, community influence). Preliminary results from multiple regression models controlling for age suggest complex relationships between social status, body size, and salivary hormone levels among the Garisakang. Male Dominance is positively related to BMI (p < 0.05) but not with salivary hormone measures, while greater male Respect is associated with reduced salivary cortisol (p = 0.06) but not testosterone or BMI. Prosociality, conversely, is not significantly related to any evaluated measure. We discuss the evolutionary implications of our findings, with a focus on future directions for investigating the biocultural interface of health in this population.

Men’s reproductive ecology and diminished hormonal regulation of skeletal muscle phenotype: An analysis of between- and within-individual variation among rural Polish men

Human life history is characterized by several distinctive features—sexual division of labor, prolonged care of altricial young, multiple dependents of different ages, and male provisioning. Testosterone has been suggested to mediate a trade-off between men’s reproduction and survival, through the regulation of sexually dimorphic musculature. This hypothesis predicts a relationship between testosterone and musculature in which mating effort, elevated testosterone, and dimorphic musculature covary positively. Testosterone is also posited to mediate a trade-off between mating and parenting effort, and accordingly, investing fathers show decreased testosterone production. Because men use their musculature not only in mating competition but also to support work demands, an important component of parenting effort, a relatively fixed relationship between testosterone and muscularity would seem maladaptive. We hypothesize that men’s parenting effort, speciﬁcally provisioning and subsistence activities, becomes a primary determinant of muscularity. Life history, anthropometric, and hormonal data were collected from 122 rural Polish men (at the Mogielica Human Ecology Study Site) during the summer harvest and for 103 of these participants in the winter. We found that fatherhood jointly predicted heavier workload and decreased testosterone, but positively predicted muscle mass and strength measures. Furthermore, within-individuals, men experienced intensiﬁed workload and suppressed testosterone during summer, along with a concomitant increase in muscularity and strength. These findings provide preliminary support for our model, termed the ‘Paternal Provisioning Hypothesis’. Between and within individuals, men’s provisioning and subsistence activities were robust predictors of muscular development and performance, whereas their testosterone levels had no appreciable effect on skeletal muscle phenotype.

Testosterone, musculature, and development in Kanyawara chimpanzees and Tsimane forager-horticulturalists

Considerable evidence suggests that the steroid hormone testosterone mediates major life-history trade-offs in primates, promoting mating effort at the expense of parenting effort or survival. In many species, chronic shifts in testosterone production over the life course correlate with investment in male-male competition. Chimpanzees and humans represent interesting test cases, because although closely related, they maintain divergent mating systems. Chimpanzee males do not invest in pair bonds or paternal care. Consequently, across the lifespan, their testosterone levels are expected to track changes in (1) behavioral investment in dominance striving, and (2) investment in sexually dimorphic musculature employed in male-male competition. Humans, by contrast, are expected to show weaker associations between testosterone and musculature, because the latter is important not only for male competition, but for men’s work provisioning wives and children. We assayed >7000 chimpanzee and >3350 Tsimane urine samples for testosterone, creatinine, and specific gravity, in the same laboratory using the same assay methods. Male chimpanzees showed peak acceleration in testosterone increase at age 6, peak velocity at age 10, and peak deceleration at age 14, reaching adult levels by 15-16, when they began to challenge other adult males. Adult levels of testosterone were achieved 3 years later than in captivity, likely reflecting energetic constraints in the wild. Indirect measures of muscle mass followed a similar pattern, and were highly correlated with testosterone. As predicted, Tsimane men exhibited a weaker correlation, with testosterone accounting for half as much variance in the muscle mass measure as in the chimpanzee sample.

Male reproductive strategies are often reduced to a ‘dad versus cad’ dichotomy. When paternity certainty is high and mating opportunities scarce, theory predicts high levels of paternal investment; if paternity certainty is low and/or access to mating opportunities plentiful, male parenting is expected to be scarce. However, conflict between mating and parenting behavior is not equally strong across ecologies and social structures. Wild mountain gorillas (Gorilla beringei) have variable paternity certainty and a morphology suggestive of intense male contest competition. Despite this, relationships between males and infants are an important component of group structure, likely because males protect infants from infanticide and predation. Using data from gorilla groups monitored by the Dian Fossey Gorilla Fund’s Karisoke Research Center, we evaluated 1) the relationship between male-infant social bond strength and males’ reproductive success, and 2) the relationship between male-infant social bonds and males’ fecal androgen metabolite levels. Higher testosterone levels are generally correlated with increased aggression and mating activity, which are typically considered incompatible with parenting behavior. After controlling for male age and rank, males who had the strongest social bonds with infants were also the males with the highest reproductive success. There was no relationship between strength of male-infant social bonds and fecal androgen metabolite levels. Results demonstrate that reductive descriptions of male reproductive strategies may obscure important connections between mating and parenting effort, and highlight the need for additional data on the relationship between androgen activity, mating, and parenting in multimale/multifemale social systems.

In an article published today (Feb. 4) in the journal Science, four scholars say racial categories are weak proxies for genetic diversity and need to be phased out. [Unraveling the Human Genome: 6 Molecular Milestones]

They've called on the U.S. National Academies of Sciences, Engineering and Medicine to put together a panel of experts across the biological and social sciences to come up with ways for researchers to shift away from the racial concept in genetics research.

"It's a concept we think is too crude to provide useful information, it's a concept that has social meaning that interferes in the scientific understanding of human genetic diversity and it's a concept that we are not the first to call upon moving away from," said Michael Yudell, a professor of public health at Drexel University in Philadelphia.

Yudell said that modern genetics research is operating in a paradox, which is that race is understood to be a useful tool to elucidate human genetic diversity, but on the other hand, race is also understood to be a poorly defined marker of that diversity and an imprecise proxy for the relationship between ancestry and genetics.

"Essentially, I could not agree more with the authors," said Svante Pääbo, a biologist and director of the Max Planck Institute for Evolutionary Anthropology in Germany, who worked on the Neanderthal genome but was not involved with the new paper. [. . .]

So what other variables could be used if the racial concept is thrown out? Pääbo said geography might be a better substitute in regions such as Europe to define "populations" from a genetic perspective. However, he added that, in North America, where the majority of the population has come from different parts of the world during the past 300 years, distinctions like "African Americans" or "European Americans" might still work as a proxy to suggest where a person's major ancestry originated.

Rooting human variation in blood or in kinship was a relatively new way to categorize humans. The idea gained strength towards the end of the Middle Ages as anti-Jewish feelings, which were rooted in an antagonism towards Jewish religious beliefs, began to evolve into anti-Semitism. These blood kinship beliefs rationalized anti-Jewish hatred instead as the hatred of a people. For example, Marranos, Spanish Jews who had been baptized, were considered a threat to Christendom by virtue of their ancestry because they could not prove purity of blood to the Inquisition.

But it's hard to imagine Yudell's ethnic neuroses could have anything to do with his totally non-tendentious (not to mention fresh, novel) advocacy for "Taking race out of human genetics". Who could disagree with his "simple goal", as stated in the concluding paragraph of his current paper: "to improve the scientific study of human difference and commonality" and "strengthen research by thinking more carefully about human genetic diversity". Please suppress any cognitive dissonance engendered by the second to last paragraph:

Phasing out racial terminology in biological sciences would send an important message to scientists and the public alike: Historical racial categories that are treated as natural and infused with notions of superiority and inferiority have no place in biology. We acknowledge that using race as a political or social category to study racism and its biological effects, although fraught with challenges, remains necessary. Such research is important to understand how structural inequities and discrimination produce health disparities in socioculturally defined groups.

Who would argue impartial, objective science is not synonymous with the promotion of minority grievance politics?

Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe (free full text):

How modern humans dispersed into Eurasia and Australasia, including the number of separate expansions and their timings, is highly debated [ 1, 2 ]. Two categories of models are proposed for the dispersal of non-Africans: (1) single dispersal, i.e., a single major diffusion of modern humans across Eurasia and Australasia [ 3–5 ]; and (2) multiple dispersal, i.e., additional earlier population expansions that may have contributed to the genetic diversity of some present-day humans outside of Africa [ 6–9 ]. Many variants of these models focus largely on Asia and Australasia, neglecting human dispersal into Europe, thus explaining only a subset of the entire colonization process outside of Africa [ 3–5, 8, 9 ]. The genetic diversity of the first modern humans who spread into Europe during the Late Pleistocene and the impact of subsequent climatic events on their demography are largely unknown. Here we analyze 55 complete human mitochondrial genomes (mtDNAs) of hunter-gatherers spanning ∼35,000 years of European prehistory. We unexpectedly find mtDNA lineage M in individuals prior to the Last Glacial Maximum (LGM). This lineage is absent in contemporary Europeans, although it is found at high frequency in modern Asians, Australasians, and Native Americans. Dating the most recent common ancestor of each of the modern non-African mtDNA clades reveals their single, late, and rapid dispersal less than 55,000 years ago. Demographic modeling not only indicates an LGM genetic bottleneck, but also provides surprising evidence of a major population turnover in Europe around 14,500 years ago during the Late Glacial, a period of climatic instability at the end of the Pleistocene.

Commentary on "Limitations of GCTA as a solution to the missing heritability problem" (abstract; pdf):

In a recent publication entitled "Limitations of GCTA as a solution to the missing heritability problem" Krishna Kumar et al. (2015 PNAS) claim that "GCTA applied to current SNP data cannot produce reliable or stable estimates of heritability". Here we show that those claims are false and that results presented by Krishna Kumar et al. are in fact entirely consistent with and can be predicted from the theory underlying GCTA.

The purported migrations that have formed the peoples of Britain have been the focus of generations of scholarly controversy. However, this has not benefited from direct analyses of ancient genomes. Here we report nine ancient genomes (~1 ×) of individuals from northern Britain: seven from a Roman era York cemetery, bookended by earlier Iron-Age and later Anglo-Saxon burials. Six of the Roman genomes show affinity with modern British Celtic populations, particularly Welsh, but significantly diverge from populations from Yorkshire and other eastern English samples. They also show similarity with the earlier Iron-Age genome, suggesting population continuity, but differ from the later Anglo-Saxon genome. This pattern concords with profound impact of migrations in the Anglo-Saxon period. Strikingly, one Roman skeleton shows a clear signal of exogenous origin, with affinities pointing towards the Middle East, confirming the cosmopolitan character of the Empire, even at its northernmost fringes.

To place our ancient genomes within a detailed British context, we next plotted these in a background PCA using 3,075 published genotypes from British3, Irish23 and southern Netherlands samples24. The modern samples were analysed using SNP genotypes at ~250,000 loci and projected into a single plot using smartpca (Fig. 3a). As in Burton et al.3 the first component of the variation was informative for the structure within Britain. Given the close ancestral relationships between these populations and their well-known history of migrational exchange, a substantial overlap between regional groups was both expected and observed. However, by considering median values, one can see a clear progression from Irish samples at one pole through Scottish, Welsh, English to the Dutch cohort at the other extreme. In this plot the York Romans cluster centrally close to the modern Welsh median value, along with the Iron-Age genome. The local Anglo-Saxon is placed differently, closest to modern East Anglians between the English and Dutch medians.

This first component also offers an opportunity to compare within the English sample. Figure 3b shows a boxplot of PC1 values for each subsample and structure is evident, with higher median values in Eastern regions such as East Anglia, East Midlands, intermediate values in the southern and western parts and lower values in the north and northwest. This pattern is more clearly seen in a geographical plot of interpolated values (Fig. 5a). When the York Romans are compared together with each modern cohort, they are most similar to the Welsh distribution of PC1 values and differ significantly from all other regional groups, apart from those from North and Northwest England (Mann–Whitney test; Fig. 3b, Supplementary Note 2 and Supplementary Table 13). An interesting difference is the marked one between the Driffield Terrace ancient and contemporary Yorkshire samples (P=0.003), implying regional discontinuity. It is also worth noting that the PC1 coordinate of the Anglo-Saxon individual is closer to the median PC1 value of East Anglians, possibly reflecting a more pronounced contribution of Germanic immigrants to eastern British populations. However, we note the inherent uncertainty in drawing inference from a single sample.